Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations, the description carries the transparency burden. It discloses meaningful behavioral facts beyond the schema: the call costs $0.01 USDC via x402, returns exactly 5 results, ranks them, and returns compact source excerpts. It does not cover auth, rate limits, or error cases, but the cost disclosure is notably useful.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Two sentences with no redundancy. The core output contract is front-loaded, and the cost is stated clearly. Every clause earns its place.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a one-parameter web search tool, the description covers the main things an agent needs: input is a query, output is 5 ranked web results with excerpts, and there is a monetary cost. The absence of an output schema is partially mitigated by mentioning the fixed JSON schema, but exact fields are still unspecified.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

There is only one required parameter, 'query', which is already documented in the schema with type, min, max, and required status. The description does not add detail about query formulation, language support, or how results are ranked. This is acceptable for a self-explanatory parameter but does not go beyond the schema.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description states a specific verb ('Return') and resource ('web results'), and adds useful specificity: 5 results, ranked, current, with compact excerpts in a fixed JSON schema. It does not explicitly differentiate from sibling tools like news_search or product_search, but the general 'web results' scope is clear enough.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description gives no guidance on when to choose web_search over alternatives such as news_search, company_search, or geographic_search. There is no mention of use cases, exclusions, or conditions that would favor a sibling tool.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.